After trial is commenced, at any time prior to the rendering of a verdict, the court may declare a mistrial on its own motion or on motion of any party if it determines an occurrence at trial has prevented a fair trial. If the court determines that the deliberate misconduct of a party or an attorney caused a mistrial, the court may require the party or the attorney, or both, to pay the reasonable expenses including attorney fees incurred by the opposing party or parties resulting from the misconduct.
Rule 48.Mistrial
Title VI: Alternative Dispute Resolution and Trial · Last amended July 1, 2016 · Last verified July 14, 2026
In one sentenceRule 48 lets a trial court declare a mistrial, on its own motion or a party's, whenever something happening during trial has made a fair trial impossible, and lets the court make a party or lawyer whose deliberate misconduct caused the mistrial pay the other side's resulting expenses.
Full Text of Rule 48
Amendment History
(Adopted March 1, 2016, effective July 1, 2016.)
Plain-English Summary
Rule 48 gives a trial judge an escape hatch when a trial goes wrong before the jury ever reaches a verdict. If something occurs during the proceedings — an outburst, a piece of evidence the jury should never have heard, any event the court decides has taken the possibility of a fair trial off the table — the judge can call a mistrial. Either side can move for one, or the court can raise it on its own. Once the jury has returned a verdict, this rule no longer applies; a party unhappy with the result at that point has to look to a motion for a new trial instead.
The rule also assigns blame where it belongs. Most mistrials happen for reasons nobody controls — an illness, an outside event, an honest mistake. But when a party or an attorney deliberately caused the mistrial, the court can order that party or attorney, or both, to cover the reasonable expenses the misconduct forced on the opposing side, including attorney fees. That shifts the cost of a wasted trial onto whoever caused it, rather than leaving the other side to absorb the expense of starting over.
Frequently Asked Questions
What can a judge declare a mistrial over?
Any occurrence during the trial that the court determines has prevented a fair trial. The rule does not list specific grounds; it leaves the determination to the trial judge's assessment of what happened and whether the trial can still produce a fair result.
Can a party ask for a mistrial, or is it only the judge's call?
Both. The court may declare a mistrial on its own motion, and either party may move for one. Either way, the request or declaration has to come before the jury renders its verdict.
Can a court still declare a mistrial after the jury reaches a verdict?
No. Rule 48 only applies before the verdict is rendered. Once the jury has returned its verdict, the available remedy for trial problems shifts to a motion for a new trial or other post-trial relief.
What happens if my own lawyer's misconduct causes a mistrial?
If the court finds that deliberate misconduct by a party or an attorney caused the mistrial, it can order that party, the attorney, or both to pay the opposing side's reasonable expenses from the misconduct, including attorney fees. A mistrial caused by something outside anyone's control does not trigger this consequence.
Does a mistrial end the case?
No. A mistrial means the current trial cannot produce a valid verdict; it does not dismiss the underlying claims. The case ordinarily gets tried again before a new jury.
Source & verification. Rule text
are reproduced verbatim from the Idaho Rules of Civil Procedure, adopted by the
Supreme Court of Idaho. Last verified July 14, 2026. ·
Official source
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